Adult Male Goats Research Articles

Sonographic characteristics of goat testis on water bath based ultrasonography

Assessing the health of the testes in domestic animals is an important aspect of the breeding soundness examination and selection. The aim of the present study was to develop a simple method for scanning and to establish ultrasonographically the gross anatomic structures of the goat testes. Six adult male goats were examined to study the sonographic appearance of normal testes and epididymides using a water bath based ultrasound scanning technique. The ultrasonographic examinations were done using a 5–9MHz/60mm (7.5MHz) linear-array transducer and a B-mode scanner. The ultrasonographic examination was performed in goats after standardizing the procedure on six testes collected from slaughter house. Results showed that in live goats when the probe was placed directly over the scrotum it gave distorted and unclear image. In water bath method the entire scrotum was dipped into a container filled with water and linear probe was used to observe the sonographic features of the testis. Each testis was viewed vertically, resulting in longitudinal image which was frozen, measured and printed through a thermal printer. The results of the ultrasonogram revealed that the testicular parenchyma was homogenous and moderately echogenic throughout. The diameter (mean±se) of the right and left testes was 4.47±0.14 and 4.42±0.07cm respectively and no significant difference was observed between the testes. The mediastinum testis was a 1.50±0.22cm wide linear structure of greater echogenicity than the testicular parenchyma when viewed in the transverse plane and nearly circular echogenic “spot” in the midline of the testis when viewed horizontally. The head and tail of the epididymides were easily identified on all the testes, but the epididymal body and ductus deferens were difficult to identify consistently. The tail of the epididymis was easily identified on the distal end of the testis with sonolucent tubules and appeared sonographically as a ‘peaked cap’ upon the testicular parenchyma. The diameter (mean±se) of the tail of right and left epididymis was 2.11±0.18 and 1.92±0.06cm and no significant difference was observed between epididymides. The vascular pampiniform plexus (1.42±0.18cm) was easily identified on the proximal end of the testes. The tunics of the testes appeared as a bright echogenic line. Inter-testicular septum appeared between testes as a hyperechoic line. It is concluded that ultrasonography permits a noninvasive evaluation of the internal structure of the scrotum and testes and water bath based sonographic examination may prove to be a valuable simple diagnostic methodology for evaluating physiopathologic conditions of goat testes and can be employed as a routine investigative method during breeding soundness and clinical examination.

Pharmacokinetic studies of meloxicam after its intravenous administration in local goat (Capra hircus) of Assam

Aim: The aim of the present study was to determine the meloxicam concentrations in the plasma of goats at different time intervals after its administration by IV route and data were used to determine the different pharmacokinetic parameters and the bioavailability of meloxicam in goats. Materials and Methods: The present study was conducted on 12 to 18 months old, five adult male local goats (Capra hircus) of Assam, with body weight ranging between 10 to 18 kg. All goats were clinically sound and healthy and reared at Goat Research station, Burnihat, Assam. A single dose of meloxicam was administered intravenously into the jugular vein of goats at the rate of 1 mg/kg body weight. Blood samples were analyzed with the help of high performance liquid chromatography (HPLC) system. Results:After single intravenous administration of meloxicam at the dose rate of 1mg/kg, the mean peak plasma level of the drug was 6.538±0.1189 μg/ml at 2 min. The mean elimination half life (t ) and mean distribution half life (t ) were 1/2â 1/2a 484.5±85.1202 min and 28.68±1.4206 min respectively. The mean values of AUC and AUMC were 2635.272±94.2389 μg.min/ml and 1620332±92456.46 μg.min2/ml respectively. The mean values of volume of distribution (Vd) and mean residence time (MRT) were 0.276±0.0103 L/kg and 612.948±14.5771 min respectively. Conclusion: After calculating various pharmacokinetic determinants, dosage regimens were computed for meloxicam in goats, based on minimum effective therapeutic plasma concentration of 0.7 μg/ml.To maintain the minimum effective concentration of 0.7 μg/ml in plasma for 25 hours following iv administration of meloxicam,an initial loading dose of 1.1 mg/kg body weight followed by a maintenance dose of 1mg/kg body weight/day is recommended.

A model of acute compression spinal cord injury by a mini-invasive expandable balloon in goats

To establish a reproducible and manipulable model of acute spinal cord compression injury in large mammals so as to provide a technical and experimental platform for the repair and reconstruction of spinal cord injury (SCI). A total of 15 adult male goats, weighting 35 - 45 kg, were selected. After intravenous anesthesia, a model of acute spinal cord compression injury was established with the balloon of kyphoplasty through mini-open laminotomy. The animals were divided into 4 groups, i.e. 3 in group A and 4 each in groups B, C and D. Goats in group A received mini-open laminotomy without insertion of balloon. In group B, balloons were surgically positioned within the T10-T11 spinal canal but not inflated. The spinal cords of goats in group C were partially compressed by inflating the balloon to approximately 30% of anterior/posterior diameter of vertebral canal. In group D, the balloon was inflated to occupy approximately 90% of canal on a lateral view. X-ray and thin-section computed tomography (CT) scans were used to determine the balloon location. CT scans were also used to calculate the magnitude of balloon inflation and the degree of spinal cord compression within vertebral canal. Improved Tarlov motor function grade test and somatosensory evoked potentials (SSEP) were employed to evaluate the goat neurofunction 24 hours before and 7 days after surgery. Dye volumes of 0, 1.26 ± 0.18 and 2.82 ± 0.20 ml were injected into the balloon to produce spinal occupancies of 0%, 33% ± 2% and 89% ± 4% on X-ray and CT scan. There was a significant dose response for the different levels of injury, with reduced conduction of somatosensory evoked potentials and impaired mobility 7 days after injury. A model of acute spinal cord injury by a tunable compression with a mini-invasive balloon in goats is a useful experiment model of spinal cord injury. It may simulate the clinical situations of acute SCI.

Methane reduction and energy partitioning in goats fed two concentrations of tannin from Mimosa spp.

SUMMARYDietary manipulation is one promising approach to reducing methane (CH4) emissions from forage-fed ruminants. Studies were conducted to evaluate the effects of feeding two concentrations of tannins from Mimosa spp. on rumen fermentation, methanogenesis and energy partitioning in goats. Adult male goats were used in three trials where three diets with increasing concentrations of tannins (control, low-tannin and high-tannin) were fed in a switch-over design. The control diet consisted of 0·65 timothy hay, 0·20 crushed maize and 0·15 soybean meal; low- and high-tannin diets contained 0·975 and 0·950 of the control diet, respectively, mixed with 0·025 and 0·050 of a commercial compound containing tannins with mean crude protein (CP) of 147 g/kg dry matter (DM) and gross energy (GE) 19 MJ/kg DM, respectively. Total contents (DM basis) of tannins (hydrolysable and condensed) in the control, low- and high-tannin diets were 0, 2·8 and 5·6 g/kg DM, respectively. The tannin source contained 37 and 76 g/kg DM of condensed and hydrolysable tannins, respectively (DM basis). The DM (664 g/d) and GE intakes (19·0 MJ/d) were similar among diet groups. Digestibilities of all dietary components in the high-tannin diet were lower (P < 0·05) than low-tannin and control diets. The faecal energy (MJ/d) output was lowest in the control diet (3·49) and increased (P < 0·05) in tannin-fed goats (3·80; 4·87) resulting in a corresponding decrease in digestible energy (DE). Methane emission, expressed both on absolute and per unit of feed intake basis, decreased (P < 0·05) with increasing concentration of tannins in the diet. For example, CH4 energy excretion was 0·98, 0·87 and 0·76 MJ/d for goats on control, low- and high-tannin diets, respectively, whereas their corresponding values for CH4 conversion ratio were 0·079, 0·069 and 0·060 of GE intake. These results suggest that natural tannins, even at a low concentration (2·8 g/kg DM of the diet), reduce CH4 emissions, and tree leaves containing appreciable amounts of tannins may potentially be exploited as natural feed additives in ruminants.

Mandibular reconstruction using an axially vascularized tissue-engineered construct

BackgroundCurrent reconstructive techniques for continuity defects of the mandible include the use of free flaps, bone grafts, and alloplastic materials. New methods of regenerative medicine designed to restore tissues depend mainly on the so-called extrinsic neovascularization, where the neovascular bed originates from the periphery of the construct. This method is not applicable for large defects in irradiated fields.MethodsWe are introducing a new animal model for mandibular reconstruction using intrinsic axial vascularization by the Arterio-Venous (AV) loop. In order to test this model, we made cadaveric, mechanical loading, and surgical pilot studies on adult male goats. The cadaveric study aimed at defining the best vascular axis to be used in creating the AV loop in the mandibular region. Mechanical loading studies (3 points bending test) were done to ensure that the mechanical properties of the mandible were significantly affected by the designed defect, and to put a base line for further mechanical testing after bone regeneration. A pilot surgical study was done to ensure smooth operative and post operative procedures.ResultsThe best vascular axis to reconstruct defects in the posterior half of the mandible is the facial artery (average length 32.5 ± 1.9 mm, caliber 2.5 mm), and facial vein (average length 33.3 ± 1.8 mm, caliber 2.6 mm). Defects in the anterior half require an additional venous graft. The defect was shown to be significantly affecting the mechanical properties of the mandible (P value 0.0204). The animal was able to feed on soft diet from the 3rd postoperative day and returned to normal diet within a week. The mandible did not break during the period of follow up (2 months).ConclusionsOur model introduces the concept of axial vascularization of mandibular constructs. This model can be used to assess bone regeneration for large bony defects in irradiated fields. This is the first study to introduce the concept of axial vascularization using the AV loop for angiogenesis in the mandibular region. Moreover, this is the first study aiming at axial vascularization of synthetic tissue engineering constructs at the site of the defect without any need for tissue transfer (in contrast to what was done previously in prefabricated flaps).

Association of Trypanosoma vivax in extracellular sites with central nervous system lesions and changes in cerebrospinal fluid in experimentally infected goats

Changes in cerebrospinal fluid (CSF) and anatomical and histopathological central nervous system (CNS) lesions were evaluated, and the presence of Trypanosoma vivax in CNS tissues was investigated through PCR. Twelve adult male goats were divided into three groups (G): G1, infected with T. vivax and evaluated during the acute phase; G2, infected goats evaluated during the chronic phase; and G3, consisting of non-infected goats. Each goat from G1 and G2 was infected with 1.25 × 105 trypomastigotes. Cerebrospinal fluid (CSF) analysis and investigation of T. vivax was performed at the 15th day post-infection (dpi) in G1 goats and on the fifth day after the manifestation of nervous system infection signs in G2 goats. All goats were necropsied, and CNS fragments from G1 and G2 goats were evaluated by PCR for the determination of T. vivax. Hyperthermia, anemia and parasitemia were observed from the fifth dpi for G1 and G2, with the highest parasitemia peak between the seventh and 21st dpi. Nervous system infection signs were observed in three G2 goats between the 30th and 35th dpi. CSF analysis revealed the presence of T. vivax for G2. Meningitis and meningoencephalitis were diagnosed in G2. PCR were positive for T. vivax in all the samples tested. In conclusion, T. vivax may reach the nervous tissue resulting in immune response from the host, which is the cause of progressive clinical and pathological manifestations of the CNS in experimentally infected goats.

Repairing goat tibia segmental bone defect using scaffold cultured with mesenchymal stem cells

In this study, we investigated cellular biocompatibility in vitro and segmental bone defect repairing efficacy in vivo of a previously reported fibre-reinforced scaffold, nano-hydroxyapatite/collagen/poly (L-lactic acid) (PLLA)/chitin fibres (nHACP/CF). First, attachment, proliferation, and differentiation of the goat bone mesenchymal stem cells (GBMSCs) cultured on the nHACP/CF scaffolds were evaluated in vitro. The results showed that cells attached to the scaffolds well, and there was no significant difference in cell proliferation between cells on the scaffolds and cells on the polystyrene culture plates that were used as a control. The results also showed that alkaline phosphatase (ALP)/DNA of the cells cultured on the scaffolds was significantly higher than that on the control. The in vivo study compared the bone defect repairing efficacy of nHACP/CF scaffolds with that of autograft bone. Thirty-two adult male goats with 25-mm defects in their tibias at the same anatomic site were divided into four groups. The first group was implanted with the nHACP/CF with GBMSCs. The second group was implanted with autograft bone. The third group was implanted with the nHACP/CF. Nothing was implanted in the fourth group. Bone growth was evaluated by radiography, histology, and biomechanics. The results showed that although the nHACP/CF had new bone formation, it could not repair the defect fully while nHACP/CF with GBMSCs cultured and autograft bone could repair the segmental bone defect by 8 weeks after surgery, suggesting that nHACP/CF is an appropriate scaffold for bone tissue engineering.

Resistance and resilience of West African Dwarf goats of the Nigerian savanna zone exposed to experimental escalating primary and challenge infections with Haemonchus contortus

We assessed the resilience and resistance to infection with Haemonchus contortus of savanna West African Dwarf (WAD) goats from northern Nigeria. Adult male goats ( n = 32) were given an escalating immunizing infection, comprising 5 weekly infections with increasing numbers of larvae. On day (D) 56 they were segregated into low (LFEC) and high (HFEC) faecal egg count phenotypes, and within each phenotype 7 goats were treated with anthelmintic and seven received no treatment. Four goats were culled for worm counts. Fourteen additional goats acted as naïve controls until D56. All, except seven naïve, were challenged with 6000 L3 of H. contortus on D63 and culled on D81, together with the seven naïve goats. The escalating infections had no effect on body weight of the goats. Neither deworming, nor challenge infection and previous experience of infection influenced body weight post-challenge (pc). There was no effect of the escalating infection on packed cell volume (PCV) of blood cells, however, the HFEC phenotypes tended to have lower values than their LFEC counterparts and controls towards the end of immunization. Virtually all goats maintained normal PCV values (28–32%) throughout, without clinical evidence of anaemia. After challenge infection the HFEC phenotypes had significantly lower PCV than the LFEC goats and naïve controls but without other symptoms of anaemia. Anthelmintic treatment had no influence on PCV pc. The anthelmintic-treated LFEC group harboured fewer worms on D18 pc than the untreated LFEC group with the superimposed challenge. In contrast anthelmintic treatment made only a small difference to the worm burdens of the HFEC group pc. In week 7 there was a strong correlation between FEC and PCV among all the goats that experienced the immunizing infection. With anthelmintic treatment taken into account, higher FEC and lower PCV in week 7 predicted higher worm burdens at the end of the experiment, but both relationships were dependent on and differed between the anthelmintic treatment groups. Overall, we found no parasitological evidence of attenuation or loss of resistance and resilience of the Nigerian savanna WAD goat ecotype to H. contortus, suggesting that significant introgression of genes from parasite-susceptible Sahelian breeds into this WAD goat population has so far not occurred.

Metabolic Conversion of Zearalenone to .ALPHA.-Zearalenol by Goat Tissues

Zearalenone (ZEA), an estrogenic mycotoxin produced by several Fusarium species, is converted into a more active metabolite, alpha-zearalenol (alpha-ZOL), and a less active metabolite, beta-zearalenol (beta-ZOL), by liver subcellular fractions, but evidence of this reaction in other tissues is limited. In order to clarify the role of various tissues in ZEA metabolism in ruminant, we investigated the in vitro metabolic conversion of ZEA by various tissues of adult male and female goats. The results indicate that in the liver, alpha-ZOL was a major metabolite in cytosolic fractions, whereas beta-ZOL was a predominant metabolite in microsome fractions. Such a feature of ZEA metabolism was confirmed by the K(m) and V(max) values from an enzyme kinetics experiment. Post-mitochondrial fractions of the liver converted ZEA predominantly to alpha-ZOL, indicating that the goat liver may function as an activation organ rather than as an inactivation organ, for ZEA metabolism in goats. In most other tissues including rumen tissue, the activity converting ZEA to alpha-ZOL was higher than that to beta-ZOL. The amount of alpha-ZOL formed by gastrointestinal tissues was 1/8-1/3 of that by the liver tissue in terms of the amount per mg protein, but the contribution of all gastrointestinal tissues to production of alpha-ZOL was estimated to be comparable to that of the liver because of the large mass of gastrointestinal tissues in ruminants. Overall the results show the importance of not only the liver tissue, but also other tissues, especially gastrointestinal ones, in the formation of a potent estrogenic metabolite, alpha-ZOL.

Effect of season on tedera ( Bituminaria bituminosa) intake by goats

The voluntary intake of three varieties of Bituminaria bituminosa ( crassiuscula, albormaginata and bituminosa), commonly called psoralea or tedera, collected in summer and winter was assessed using adult male goats. Dry matter (DM) content of varieties ranged from 221 to 281 g per kg fresh varieties, and chemical composition (per kg DM) of varieties ranged from 866 to 915 g organic matter, 150 to 202 g crude protein and 411 to 532 g neutral detergent fibre. In vitro OM digestible content ranged from 514 to 564 g/kg DM and it did not differ among varieties or season. When goats could choose among forages, including alfalfa hay, they consumed 0.71–0.88 of the offered tedera varieties and only a third of the offered alfalfa hay in the winter study. However, in summer, goats consumed all the offered alfalfa hay and only about a third of each offered tedera varieties, probably because of the secondary compounds in the fruits and seeds. Moreover, when preference for tedera hay or alfalfa hay was compared, daily intake of goats was composed by 0.67 tedera hay and 0.33 alfalfa hay. This research showed a goat preference for tedera (in fresh or as hay) than for alfalfa hay, except for fresh tedera collected in summer. However, haymaking overcomes this problem.

Rut‐Induced Hypophagia in Male Bighorn Sheep and Mountain Goats: Foraging Under Time Budget Constraints

AbstractIn polygynous ungulates, the rut imposes constraints on male time budgets that generate a trade‐off between maintenance and reproduction, leading to a reduction in time spent foraging. As mating activities can incur substantial somatic costs, males are expected to spend their ‘non‐rutting’ time recovering during the breeding season. If the diminution in time allocated to foraging by males is only a consequence of time budget constraints, males should keep a similar ratio of time spent foraging to lying to that observed in the pre‐rut, leading to an overall reduction of these two activities (the ‘foraging constraint’ hypothesis). Alternatively, if males adopt an energy‐saving strategy, they should limit energy expenditures by reducing foraging but not lying time, as the energy gains of forage intake may not meet the basal energetic requirements, especially in northern and temperate regions (the ‘energy‐saving’ hypothesis). Here, we contrast these two hypotheses by comparing individual daily time budgets of marked adult bighorn sheep rams (Ovis canadensis) and male mountain goats (Oreamnos americanus) during the pre‐rut and the rut. Concordant results for both species support the ‘foraging constraint’ hypothesis, as sexually‐active males reduced time spent foraging and lying from the pre‐rut to the rut because of an increase in time spent in mating‐related activities. Bighorn sheep rams also increased time spent foraging when not engaged in mating tactics, providing further support for a ‘maximisation’ of energy intake in the absence of reproductive opportunities. Because there are also known physiological changes that occur during the rut which may cause appetite suppression, for example to produce metabolic compounds linked with olfactory communication (the ‘scent‐urination’ hypothesis) or to cope with increased burden of parasites (the ‘parasite‐induced anorexia’ hypothesis), further research should aim at simultaneously testing these current hypotheses to better understand rut‐induced hypophagia and its effects on the life histories of male ungulates.

Seasonal variations of phagocytic response, immunoglobulin G (IgG) and plasma cortisol levels in Dhofari goats

Unpublished observations in Oman revealed that both the morbidity and mortality figures for a wide variety of diseases in goats are higher during the winter than during the summer season. The present study therefore, attempted to ascertain whether there were any measurable seasonal differences in the phagocytic response, levels of circulating immunoglobulin G, blood cells or plasma cortisol in six adult male Dhofari goats investigated over a 1-year period. Interestingly, we observed that during the summer, goats had significantly higher levels of circulating lymphocytes, increased phagocytic activity against the bacterial target, Staphylococcus aureus and lower levels of plasma cortisol. It was postulated that the decreased phagocytic activity observed during the winter season might be related to reduced levels of opsonins, early neutrophil exhaustion and/or suppression of neutrophil activity as a result of higher cortisol levels and reduced periods of exposure to daylight. These results might also explain in part why the incidence of a variety of diseases in goats is commonly higher during the winter season.

High fertility using artificial insemination during deep anoestrus after induction and synchronisation of ovulatory activity by the “male effect” in lactating goats subjected to treatment with artificial long days and progestagens

The response to the male effect was studied in two Saânen and two Alpine flocks over 5 consecutive years. Adult male and female goats were exposed to artificial long days (16 h light and 8 h darkness, 16L:8D) in open barns for approximately 3 months (between December 1 and April 15) followed by a natural photoperiod. Goats were treated for 11 days with fluorogestone acetate (FGA) or progesterone (CIDR) immediately before joining. Bucks carrying marking harnesses with adapted aprons joined females 49–63 days after the end of the long-day treatment (between April 30 and June 5) and were left with them for 5 days. In experiment 1 ( n = 142), FGA- and CIDR-treated goats were inseminated at a time based on the detection of oestrus. Two insemination groups were distinguished by the occurrence of marking over a 48-h period. Earlier (group 1) and later (group 2) buck-marked goats received one single insemination 12–24 h or 0–12 h after marking, respectively. Unmarked goats were inseminated along with group 2. In experiment 2 ( n = 344), FGA-treated goats were inseminated 52 and 70 h (52 h:70 h group) or 52 and 75 h (52 h:75 h group) after joining. In experiment 3 ( n = 285), FGA-treated goats were inseminated 52 h (1-AI group) or 52 and 75 h (2-AI group) after joining. In all experiments, an external control group given the “classical” insemination program was analysed. Over the 5-year period, 92% of the goats exhibited an LH surge during days 1–4 after joining and 98% of them ovulated. Eighty-seven percent of the LH surges detected in milk occurred during the 33–57 h interval after joining, indicating that ovulation took place around 45–69 h. In experiment 1, 96% of the goats were marked 22–70 h after joining. Kidding rate (KR; 78%) was similar between insemination groups and between FGA- and CIDR-treated goats ( p > 0.05). Most of the goats (95%) were inseminated during the interval between 15 h before and up to 4 h after ovulation. KR was not affected by the time between detection of marking and insemination or between insemination and ovulation ( p > 0.05). In experiment 2, KR (75%) was similar in both insemination groups ( p > 0.05). In experiment 3, KR was higher ( p < 0.05) in the 1-AI (71%) than the 2-AI group (57%). In all experiments, KR of the control group (68–73%) was similar to that achieved in goats induced to ovulate by the male effect. Prolificity (2.1 ± 0.7) was not affected by any of the factors examined ( p > 0.05). In conclusion, high fertility can be achieved during anoestrus when 1 or 2 inseminations are performed over a 24 h period, determined by oestrus or by the introduction of the buck, if light-treated goats receive 11-day FGA or CIDR treatment and are then induced to ovulate by the male effect.

Parity of female goats does not influence their estrous and ovulatory responses to the male effect

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1900 h, a group of multiparous females ( n = 21) and a group of 16 months-old nulliparous females ( n = 19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ ( P > 0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ ( P > 0.05) between multiparous (1.9 ± 0.1 days) and nulliparous (1.7 ± 0.2 days) females. The proportion of females displaying a short estrous cycle was greater ( P < 0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ ( P > 0.05) between groups (multiparous: 5.2 ± 0.3 days, nulliparous: 4.5 ± 0.1 days). The number of anogenital sniffings was greater ( P < 0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater ( P < 0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different ( P > 0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.

Effects of Non-protein Energy Intake on Whole Body Protein Synthesis, Nitrogen Retention and Glucose Turnover in Goats

The responses of whole body protein and glucose kinetics and of nitrogen (N) metabolism to non-protein energy intake (NPEI) were determined using an isotope dilution approach and measurement of N balance in three adult male goats. The diets containing 1.0, 1.5 and 2.0 times ME maintenance requirement, with fixed intake of CP (1.5 times maintenance) and percentage of hay (33%), were fed twice daily for each 21 d experimental period. After an adaptation period of 11 d, N balance was determined over 3 d. On day 17, whole body protein synthesis (WBPS) and glucose irreversible loss rate (ILR) were determined during the absorptive state by a primed-continuous infusion of []phenylalanine, []tyrosine, []tyrosine and []glucose, with simultaneous measurements of plasma concentrations of metabolites and insulin. Ruminal characteristics were also measured at 6 h after feeding over 3 d. Nitrogen retention tended to increase (p) that of tyrosine. Whole body protein synthesis increased (p). These results suggest that increasing NPEI may enhance WBPS and glucose turnover at the absorptive state and improve the efficiency of digestible N retention in goats, with possibly decreased ammonia and increased amino acid absorption. In addition, simultaneous increases in WBPS and glucose ILR suggest stimulatory effect of glucose availability on WBPS, especially when sufficient amino acid is supplied.

Effects of Dietary Starch and Sucrose on Tissue Responsiveness and Sensitivity to Insulin in Goats Fed a High-concentrate Diet

A glucose clamp technique was used to compare dietary starch (ST), starch plus sucrose (ST+SU) and sucrose (SU) with regard to the effect on tissue responsiveness and sensitivity to insulin in intact adult male goats. The goats were fed diets containing 1.2 times of ME and CP for maintenance requirements twice daily for 21 d. Of the energy intake, 30% was offered with ST, ST+SU or SU for the respective diets, and 70% as alfalfa hay, ground corn and ground soybean meal at the respective weight ratio of 1, 1, and 0.3 for all diets. Tissue responsiveness and sensitivity to insulin were evaluated using a hyperinsulinemic euglycemic clamp technique with four levels of insulin infusion beyond 13 h after feeding. The concentrations of plasma metabolites and insulin were also determined at 3, 6 and 13 h after feeding to evaluate the effects of different carbohydrates on metabolic states in the body. Plasma glucose concentration was higher (p = 0.01) for SU diet than for ST and ST+SU diets. Increasing SU intake decreased (p<0.01) plasma acetate concentration across the time. At 3 h but not 6 and 13 h after feeding, high lactate (p = 0.01), and non-significant high propionate (p = 0.14) and low urea nitrogen (p = 0.19) concentrations were observed in plasma on SU compared with ST and ST+SU diets. Plasma insulin concentration was not different (p = 0.44) between ST and SU fed animals. In the glucose clamp experiment, considering the effects on the maximal glucose infusion rate (tissue responsiveness to insulin, p = 0.54) and the plasma insulin concentration at half-maximal glucose infusion rate (insulin sensitivity, p = 0.54), SU was not different from ST. It is concluded that SU may not be greatly different from ST with regard to the effect on tissue responsiveness and sensitivity to insulin in adult goats when fed twice daily as part of a high-concentrate diet. The possible greater effects of SU on plasma metabolites concentrations at 3 h than at 6 and 13 h after feeding suggest that a lack of persistency of SU effects during the postfeeding period may be associated with the poor response to SU in insulin action.

Abstracted Proceedings from The International Cardiac Bioassist Conference, November 8-10, 2005, Fort Collins, Colorado, USA

Abstracted Proceedings from The International Cardiac Bioassist Conference, November 8-10, 2005, Fort Collins, Colorado, USA

Effects of Non-protein Energy Intake on the Concentrations of Plasma Metabolites and Insulin, and Tissue Responsiveness and Sensitivity to Insulin in Goats

A glucose clamp technique was used to investigate the effects of non-protein energy intake on tissue responsiveness and sensitivity to insulin for glucose metabolism in intact adults male goats. Three goats were fed diets at 1.0, 1.5 and 2.0 times of ME for maintenance, each for 21 d. Crude protein intake was 1.5 times of maintenance requirement in each treatment. Tissue responsiveness and sensitivity to insulin were evaluated using a hyperinsulinemic euglycemic clamp technique with four levels of insulin infusion, beginning at 13 h after feeding. Concentrations of plasma metabolites and insulin were also measured at 3, 6 and 13 h after feeding, for evaluating effects of non-protein energy intake on the metabolic status of the animals. Increasing non-protein energy intake prevented an increase in plasma NEFA concentration at 13 h after feeding (p = 0.03). Plasma urea-nitrogen and total amino-nitrogen concentrations decreased (p<0.01) and increased (p = 0.03), respectively, with increasing non-protein energy intake across time relating to feeding. Plasma insulin concentration was unaffected (p = 0.43) by non-protein energy intake regardless of time relating to feeding. In the glucose clamp experiment, increasing non-protein energy intake decreased numerically (p = 0.12) the plasma insulin concentration at half-maximal glucose infusion rate (insulin-sensitivity), but did not affect (p = 0.60) maximal glucose infusion rate (tissue responsiveness to insulin). The present results suggest that an increase in non-protein energy intake may enhance insulin sensitivity for glucose metabolism, unlike responsiveness to insulin, in adult male goats. The possible enhancement in insulin sensitivity may play a role in establishing anabolic status in the body, when excess energy is supplied to the body.

Collagen-based implants reinforced by chitin fibres in a goat shank bone defect model

Tissue engineering is an increasingly popular method for repairing bone defects. However, repair of bone defects over 30 mm using tissue-engineering methods is a difficult clinical problem. In this study, we used a goat shank model to evaluate the bone-regenerating efficacy of a novel nano-hydroxyapatite/collagen/PLLA (nHACP) composite reinforced by chitin fibres. Forty adult male goats with 40 mm defects in shank at the same anatomic site were divided into four groups. The first group was the control, where nothing was implanted in the defect (defect group). The other three groups were implanted with porous pure PLLA, nHACP and nHACP reinforced by chitin fibres, respectively. Bone growth in each group was evaluated by radiography, histology, bone mineral density and mechanical strength, once every 5 weeks for 15 weeks. The results indicated that nHACP implants, both with and without chitin fibres, are better for repairing the defects than pure PLLA. However, only the reinforced implants showed nearly perfect recovery in 15 weeks after operation. So, the reinforced scaffold might be a candidate for bone tissue repair.

Evaluation of single intratesticular injection of calcium chloride for nonsurgical sterilization of male Black Bengal goats ( Capra hircus): a dose-dependent study

This study describes the induction of chemosterilization in three groups each of six adult male Black Bengal goats at 30 days after a single bilateral intratesticular injection of a calcium chloride (CaCl 2, 2H 2O) solution at the doses of 10, 20 or 40 mg/kg body weight/testis, always in a 2 ml volume of normal saline. Another one group of animals received only 2 ml of normal saline per testis as a control. The induction of chemosterilization was measured using relative testicular weight as well as histomorphological parameters including seminiferous tubular architecture and germ cell association in seminiferous tubules along with morphology of the interstitial space. Biochemical markers included activities of testicular Δ 5, 3β-hydroxysteroid dehydrogenase (Δ 5, 3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST) and superoxide dismutase (SOD) as well as monitoring the level of testicular thiobarbituric acid reactive substances (TBARS), conjugated dienes and reduced glutathione (GSH) content along with plasma concentrations of testosterone, LH and FSH. Histomorphological measures of testes showed total necrosis of testicular tissue at 30 days after an injection of either 20 or 40 mg CaCl 2 along with fibrosis in seminiferous tubules and interstitial spaces. Infiltration of leucocytes was observed with the 40 mg dose. Disintegration of germ cell arrangement in seminiferous tubules and washing out of germ cells from the tubules were noted with the 10 mg dose. Relative organ weights, plasma concentrations of testosterone, testicular activities of Δ 5, 3β-HSD, 17β-HSD, catalase, GPx, GST, and SOD and testicular contents of GSH all were declined. Increases occurred in testicular TBARS, conjugated dienes and plasma concentrations of LH and FSH with each of the treatments by comparison with the control group. Plasma concentrations of cortisol and fasting blood sugar level as well as packed cell volume (PCV) and total plasma protein were recorded to monitor the changes of chronic stress in the experimental animals. Changes in these parameters were not significant. An intratesticular injection of calcium chloride at specified doses could be a suitable method of sterilization in preference to surgical castration of goats.